1. Field of the Invention
The present invention relates to a sampler for automatic elemental analyzers including a pyrolytic unit, particularly a sampler of the fully tight, sealed type.
2. Description of the Related Art
An elemental analyzer, including a pyrolytic unit internally or aside, is an instrument intended for analyzing the elemental composition in samples of solid or liquid materials, usually accommodated in e.g. tin or silver cups using oxygen for combustion and carbon for pyrolytic reduction generating gas as reaction products. An elemental analyzer comprises a sampler for introducing the sample suitably prepared e.g. in said tin or silver cups or adsorbed in inert material if liquids into a combustion or pyrolytic reactor of the analyzer itself. The elemental analyzer further comprises a furnace in which reactor tubes for combustion (usually at temperatures higher than 900° C.) or pyrolytic reaction (usually at temperatures between 1200-1500° C. or more) are accommodated for sample combustion or pyrolysis.
Samples thus converted into a gas mixture flow through a trap to eventually eliminate water or acidic gas and a gas chromatography column which allows the gas to be time separated and then detected by a TCD for stand alone application providing element % result in the mixture; the separated gas can be further analyzed in their isotopic composition entering in continuous flow in an Isotopic Ratio Mass Spectrometer to provide Isotopic Ratio composition of the isotopes included in each element. A pneumatic circuit is provided capable of creating a continuous flow of carrier gas, for example Helium or Argon.
Many sampler are known in the art.
An example of a known non-sealed type of sampler is disclosed in the Utility model no. TO2001 U 000175 in the name of the present Applicant.
A problem of the known samplers for elemental analyzers used in combustion or pyrolysis is that samples can contains traces of residual adsorbed gas, water, vapor or other compound present on the samples as they are, or resulting from pre-treatments or storage. These unwanted material can affect element % results in stand alone combustion and pyrolytic application and indeed isotopic ratio accuracy.